Answer:
|x - 13| = 5
Explanation:
Think of absolute value as a distance. For example, |5| can be written as |5 - 0| = 5 since the distance between 5 and zero on the number line is 5. Also, |-5| which is the same as |-5 - 0| is also 5 since the distance between -5 and zero on the number line is 5.
Since you want an absolute value equation with solutions 8 and 18, think of which number is the same distance from both 8 and 18 on the number line? Find the average of 8 and 18, (8 + 18)/2 = 13. 13 is the same distance from both 8 and 18. 13 is 5 units away from both 8 and 18. Now you need an equation that is looking for the numbers x which are 5 units distance from 13.
|x - 13| = 5